You will need:
Guitar Hero controller
Size 10 Torx screwdriver
Small philips screwdriver
Large-ish flat screwdriver
Duct tape (I used black "Duck" tape)
"Blu-tack", or other poster adhesive putty (e.g. "white-tack")
This idea is not mine as people have done similar things before, but there is no instructable, or indeed any clear set of instructions that I could find. And I haven't found any examples of people doing it to a Guitar Hero 3 controller, although the principle is the same for other GH guitar versions.
This is my first instructable so please be kind :)
Step 1: Remove all screws in the guitar neck
You will need a size 10 Torx screwdriver for this.
Step 2: Open neck
Step 3: Dismantle fret button assembly
Use a large-ish flat screwdriver to remove the circuit board. It is quite a tight fit on the plastic posts, but if you're careful you shouldn't damage the board.
Carefully lift the circuit board and set it aside. Be particularly careful not to trap or fold the ribbon cable at any point as it's quite delicate.
Remove the blue rubber pad from the buttons, and set it aside - this will reveal the fret buttons. You can now remove these too.